Tryptase Promotes the Profibrotic Phenotype Transfer of Atrial Fibroblasts by PAR2 and PPARγ Pathway

SerpinB3: A Multifaceted Player in Health and Disease-Review and Future Perspectives

SerpinB3, a member of the serine-protease inhibitor family, has emerged as a crucial player in various physiological and pathological processes. Initially identified as an oncogenic factor in squamous cell carcinomas, SerpinB3's intricate involvement extends from fibrosis progression and cancer to cell protection in acute oxidative stress conditions. This review explores the multifaceted roles of SerpinB3, focusing on its implications in fibrosis, metabolic syndrome, carcinogenesis and immune system impairment. Furthermore, its involvement in tissue protection from oxidative stress and wound healing underscores its potential as diagnostic and therapeutic tool. Recent studies have described the therapeutic potential of targeting SerpinB3 through its upstream regulators, offering novel strategies for cancer treatment development. Overall, this review underscores the importance of further research to fully elucidate the mechanisms of action of SerpinB3 and to exploit its therapeutic potential across various medical conditions.

The protease activated receptor 2 - CCAAT/enhancer-binding protein beta - SerpinB3 axis inhibition as a novel strategy for the treatment of non-alcoholic steatohepatitis

OBJECTIVE

The serine protease inhibitor SerpinB3 has been described as critical mediator of liver fibrosis and it has been recently proposed as an additional hepatokine involved in NASH development and insulin resistance. Protease Activated Receptor 2 has been identified as a novel regulator of hepatic metabolism. A targeted therapeutic strategy for NASH has been investigated, using 1-Piperidine Propionic Acid (1-PPA), since this compound has been recently proposed as both Protease Activated Receptor 2 and SerpinB3 inhibitor.

METHODS

The effect of SerpinB3 on inflammation and fibrosis genes was assessed in human macrophage and stellate cell lines. Transgenic mice, either overexpressing SerpinB3 or carrying Serpinb3 deletion and their relative wild type strains, were used in experimental NASH models. Subgroups of SerpinB3 transgenic mice and their controls were also injected with 1-PPA to assess the efficacy of this compound in NASH inhibition.

RESULTS

1-PPA did not present significant cell and organ toxicity and was able to inhibit SerpinB3 and PAR2 in a dose-dependent manner. This effect was associated to a parallel reduction of the synthesis of the molecules induced by endogenous SerpinB3 or by its paracrine effects both in vitro and in vivo, leading to inhibition of lipid accumulation, inflammation and fibrosis in experimental NASH. At mechanistic level, the antiprotease activity of SerpinB3 was found essential for PAR2 activation, determining upregulation of the CCAAT Enhancer Binding Protein beta (C/EBP-β), another pivotal regulator of metabolism, inflammation and fibrosis, which in turn determined SerpinB3 synthesis.

CONCLUSIONS

1-PPA treatment was able to inhibit the PAR2 - C/EBP-β - SerpinB3 axis and to protect from NASH development and progression, supporting the potential use of a similar approach for a targeted therapy of NASH.

Effects of low-dose oxygen ions on cardiac function and structure in female C57BL/6J mice

PURPOSE

Astronauts in space vehicles beyond low-Earth orbit will be exposed to high charge and energy (HZE) ions, and there is concern about potential adverse effects on the cardiovascular system. Thus far, most animal studies that assess cardiac effects of HZE particles have included only males. This study assessed the effects of oxygen ions (¹⁶O) as a representative ion of the intravehicular radiation environment on the heart of female mice.

MATERIALS AND METHODS

Female C57BL/6 J mice at 6 months of age were exposed to ¹⁶O (600 MeV/n) at 0.25-0.26 Gy/min to a total dose of 0, 0.1, or 0.25 Gy. Cardiac function and abdominal aorta blood velocity were measured with ultrasonography at 3, 5, 7, and 9 months after irradiation. At 2 weeks, 3 months, and 9 months, cardiac tissue was collected to assess collagen deposition and markers of immune cells.

RESULTS

Ultrasonography revealed increased left ventricle mass, diastolic volume and diameter but there was no change in the abdominal aorta. There was no indication of cardiac fibrosis however, a 75 kDa peptide of left ventricular collagen type III and α-smooth muscle cell actin were increased suggesting some remodeling had occurred. Left ventricular protein levels of the T-cell marker CD2 was significantly increased at all time points, while the neutrophil marker myeloperoxidase was decreased at 2 weeks and 9 months.

CONCLUSIONS

These results taken together suggest ¹⁶O ion exposure did not result in cardiac fibrosis or cardiac dysfunction in female mice. However, it does appear mild cardiac remodeling occurs in response to HZE radiation.

Two Sides of the Coin: Mast Cells as a Key Regulator of Allergy and Acute/Chronic Inflammation

It is well known that mast cells (MCs) initiate type I allergic reactions and inflammation in a quick response to the various stimulants, including—but not limited to—allergens, pathogen-associated molecular patterns (PAMPs), and damage-associated molecular patterns (DAMPs). MCs highly express receptors of these ligands and proteases (e.g., tryptase, chymase) and cytokines (TNF), and other granular components (e.g., histamine and serotonin) and aggravate the allergic reaction and inflammation. On the other hand, accumulated evidence has revealed that MCs also possess immune-regulatory functions, suppressing chronic inflammation and allergic reactions on some occasions. IL-2 and IL-10 released from MCs inhibit excessive immune responses. Recently, it has been revealed that allergen immunotherapy modulates the function of MCs from their allergic function to their regulatory function to suppress allergic reactions. This evidence suggests the possibility that manipulation of MCs functions will result in a novel approach to the treatment of various MCs-mediated diseases.

Significance of Mast Cell Formed Extracellular Traps in Microbial Defense

Mast cells (MCs) are critically involved in microbial defense by releasing antimicrobial peptides (such as cathelicidin LL-37 and defensins) and phagocytosis of microbes. In past years, it has become evident that in addition MCs may eliminate invading pathogens by ejection of web-like structures of DNA strands embedded with proteins known together as extracellular traps (ETs). Upon stimulation of resting MCs with various microorganisms, their products (including superantigens and toxins), or synthetic chemicals, MCs become activated and enter into a multistage process that includes disintegration of the nuclear membrane, release of chromatin into the cytoplasm, adhesion of cytoplasmic granules on the emerging DNA web, and ejection of the complex into the extracellular space. This so-called ETosis is often associated with cell death of the producing MC, and the type of stimulus potentially determines the ratio of surviving vs. killed MCs. Comparison of different microorganisms with specific elimination characteristics such as S pyogenes (eliminated by MCs only through extracellular mechanisms), S aureus (removed by phagocytosis), fungi, and parasites has revealed important aspects of MC extracellular trap (MCET) biology. Molecular studies identified that the formation of MCET depends on NADPH oxidase-generated reactive oxygen species (ROS). In this review, we summarize the present state-of-the-art on the biological relevance of MCETosis, and its underlying molecular and cellular mechanisms. We also provide an overview over the techniques used to study the structure and function of MCETs, including electron microscopy and fluorescence microscopy using specific monoclonal antibodies (mAbs) to detect MCET-associated proteins such as tryptase and histones, and cell-impermeant DNA dyes for labeling of extracellular DNA. Comparing the type and biofunction of further MCET decorating proteins with ETs produced by other immune cells may help provide a better insight into MCET biology in the pathogenesis of autoimmune and inflammatory disorders as well as microbial defense.

Biomarkers and Their Possible Functions in the Intestinal Microenvironment of Chagasic Megacolon: An Overview of the (Neuro)inflammatory Process

The association between inflammatory processes and intestinal neuronal destruction during the progression of Chagasic megacolon is well established. However, many other components play essential roles, both in the long-term progression and control of the clinical status of patients infected with Trypanosoma cruzi. Components such as neuronal subpopulations, enteric glial cells, mast cells and their proteases, and homeostasis-related proteins from several organic systems (serotonin and galectins) are differentially involved in the progression of Chagasic megacolon. This review is aimed at revealing the characteristics of the intestinal microenvironment found in Chagasic megacolon by using different types of already used biomarkers. Information regarding these components may provide new therapeutic alternatives and improve the understanding of the association between T. cruzi infection and immune, endocrine, and neurological system changes.

Regulation of Pancreatic Fibrosis by Acinar Cell-Derived Exosomal miR-130a-3p via Targeting of Stellate Cell PPAR-γ

Introduction

As endogenous miRNA carriers, exosomes play a role in the pathophysiological processes of various diseases. However, their functions and regulation mechanisms in pancreatic fibrosis remain unclear.

Methods

In this study, an RNA microarray was used to detect differentially expressed exosomal miR-130a-3p in AR42J cells before and after taurolithocholate (TLC) treatment. mRNA-seq was used to screen differentially expressed genes before and after pancreatic stellate cell (PSC) activation. We used the STRING database to construct a protein-protein interaction (PPI) network for differentially expressed genes, used CytoNCA to analyze the centrality of the PPI network, and identified 10 essential proteins in the biological network. Then, the TargetScan and miRanda databases were used to predict the target genes of miR-130a-3p. The intersections of the target genes and the mRNAs encoding the 10 essential proteins were identified to construct miR-130a-3p/peroxisome proliferator-activated receptor gamma (PPAR-γ) pairs. Fluorescence labeling of exosomes and dynamic tracing showed that exosomes can fuse with the cell membranes of PSCs and transport miR-130a-3p into PSCs. A luciferase reporter gene assay was used to confirm that miR-130a-3p can bind to PPAR-γ to inhibit PPAR-γ expression. In vitro and in vivo functional experiments were performed for gain-of-function studies and loss-of-function studies, respectively.

Results

The studies showed that acinar cell-derived exosomal miR-130a-3p promotes PSC activation and collagen formation through targeting of stellate cellular PPAR-γ. Knockdown of miR-130a-3p significantly improved pancreatic fibrosis. Notably, miR-130a-3p knockdown reduced serum levels of hyaluronic acid (HA) and β-amylase and increased the C-peptide level to protect endocrine and exocrine pancreatic functions and the function of endothelial cells.

Conclusion

This study revealed that the exosomal miR-130a-3p/PPAR-γ axis participates in PSC activation and the mechanism of chronic pancreatitis (CP) with fibrosis, thus providing a potential new target for the treatment of chronic pancreatic fibrosis.

Mast Cell Tryptase Promotes Inflammatory Bowel Disease-Induced Intestinal Fibrosis

BACKGROUND

Intestinal fibrosis is the final pathological outcome of chronic intestinal inflammation without specific therapeutic drugs, which leads to ileus and surgical intervention. Intestinal fibrosis is characterized by excessive deposition of extracellular matrix (ECM). The role of mast cells (MCs), which are members of the sentinel immune cell population, is unknown in intestinal fibrosis.

METHODS

In this study, we analyzed changes in MCs, tryptase proteins, and ECM components in human fibrotic and control patient intestines. We constructed dextran sodium sulfate-induced intestinal fibrosis models using wild-type mice, MC-reconstituted mice, and MC-deficient mice to explore the role of MCs and tryptase in intestinal fibrosis. The roles and mechanisms of MCs and tryptase on fibroblasts were evaluated using human MCs (HMC-1 and LAD-2), commercial tryptase proteins, human colon fibroblasts (CCD-18Co fibroblasts), the tryptase inhibitor APC366, and the protease-activated receptor-2 (PAR-2) antagonist ENMD-1068.

RESULTS

Regardless of whether the colon was a human colon or a mouse colon, the fibrotic intestinal tissue had increased MC infiltration and a higher expression of ECM proteins or genes than that of the control group. The dextran sodium sulfate-induced intestinal fibrosis in MC-deficient mice was alleviated compared with that in wild-type mice. After MC reconstruction in MC-deficient mice, the alleviating effect disappeared. Tryptase, as a content stored in MC granules, was released into fibrotic intestinal tissues in the form of degranulation, resulting in an increased expression of tryptase. Compared with the control group, the tryptase inhibition group (the APC366 group) had reduced intestinal fibrosis. The CCD-18Co fibroblasts, when cocultured with MCs or treated with tryptase proteins, were activated to differentiate into myofibroblasts and secrete more ECM proteins (such as collagen and fibronectin). The underlying mechanism of fibroblast activation by tryptase was the activation of the PAR-2/Akt/mTOR pathway.

CONCLUSIONS

We found that MC tryptase promotes inflammatory bowel disease-induced intestinal fibrosis. The underlying mechanism is that tryptase promotes the differentiation of fibroblasts into fibrotic-phenotype myofibroblasts by activating the PAR-2/Akt/ mTOR pathway of fibroblasts.

[Alkaline processing of cantharidin can significanty improve the antitumor activity of cantharidin]

OBJECTIVE

To assess the changes in the effects of cantharides after alkaline processing on proliferation, migration, invasion, and apoptosis of human lung cancer A549 cells.

METHODS

Human non-small cell lung cancer A549 cells were treated with cantharis extract (CTE) from raw cantharides and alkali processed cantharis extract (ACE). The proliferation of the cells was detected with CCK-8 assay, and the cell migration and invasion were assessed using wound healing assay and Transwell assay, respectively. The expressions of MMP1 and MMP2 in the cells were detected using Western blotting, the contents of IFN-γ, IL-1β and TNF-α were measured with ELISA, and cell apoptosis was analyzed with annexinV/PI fluorescent staining.

RESULTS

Both CTE and ACE significantly reduced the viability and inhibited the migration of A549 cells, and high-dose ACE produced a significantly stronger inhibitory effect on cell migration than high- dose CTE (P < 0.01). ACE showed more potent inhibitory effect than CTE on the invasion of A549 cells (P < 0.01). Both CTE and ACE inhibited the expressions of MMP1 and MMP2 and up-regulated the level of IFN-γ without significantly affecting the levels of IL-1β and TNF-α. Annexin V/PI staining showed that both CTE and ACE caused apoptosis of A549 cells, but ACE had a stronger proapoptotic effect.

CONCLUSIONS

Processing with sodium hydroxide can significantly improve the antitumor activity of cantharides, which inhibits the proliferation, migration and invasion of A549 cells possibly by down-regulating the expressions of MMP1 and MMP2, promoting apoptosis and increasing the level of IFN-γ.

Circ_BMP2K enhances the regulatory effects of miR-455-3p on its target gene SUMO1 and thereby inhibits the activation of cardiac fibroblasts

Research has shown that some circular RNAs (circRNA) are abnormally expressed in the process of myocardial fibrosis, but the mechanism behind this was unknown. In the process of inducing cardiac fibroblast (CF) activation with TGF-β1 or Ang II, the expression of circRNA circ_BMP2K and miR-455-3p were significantly inhibited, whereas the expression of SUMO1 was promoted. The results from our dual luciferase reporter gene assays, RIP assays, and pull-down assays show that miR-455-3p directly binds circ_BMP2K, thereby mutually promoting their expression levels. SUMO1 is a target gene of miR-455-3p, and circ_BMP2K enhances the inhibitory effects of miR-455-3p on the expression of SUMO1. Further study showed that both circ_BMP2K and miR-455-3p inhibited the expression of alpha-SMA as well as type I and type III collagen, whereas SUMO1 promoted their expression, and miR-455-3p inhibitors or overexpression of SUMO1 reversed the effects of circ_BMP2K and miR-455-3p. Circ_BMP2K and miR-455-3p inhibits cell proliferation and migration and promotes the apoptosis of CFs, but SUMO1 has the opposite effects; miR-455-3p inhibitors or overexpression of SUMO1 reverses the effects of circ_BMP2K and miR-455-3p. Thus, circ_BMP2K promotes the expression of miR-455-3p, down-regulates the expression of SUMO1, and finally, inhibits the activation, growth, and migration of CFs. These results could provide important therapeutic targets and a theoretical basis for regulating the process of myocardial fibrosis.

Mast cells and collagen fibrillogenesis

This article presents 20 combinations of histochemical stainings for the determination of mast cell co-localization with the fibrous component of the connective tissue in the fibrillogenesis course. Best results were obtained using metachromatic detection of mast cells in combination with silver or picro-fuchsin impregnation, staining with brilliant green using van Gieson staining, and a combination of aniline blue staining with neutral red. Proposed variants of histochemical protocols open up new opportunities to analyze the participation of mast cells in extracellular matrix remodeling of the tissue microenvironment in the course of adaptive and pathological processes. Results obtained expand the current theoretical views of the process of fibrillogenesis in the extracellular matrix. They also shed new light on the participation of mast cell secretion components in the molecular mechanisms of fiber formation.

The emerging role of mast cell proteases in asthma

It is now well established that mast cells (MCs) play a crucial role in asthma. This is supported by multiple lines of evidence, including both clinical studies and studies on MC-deficient mice. However, there is still only limited knowledge of the exact effector mechanism(s) by which MCs influence asthma pathology. MCs contain large amounts of secretory granules, which are filled with a variety of bioactive compounds including histamine, cytokines, lysosomal hydrolases, serglycin proteoglycans and a number of MC-restricted proteases. When MCs are activated, e.g. in response to IgE receptor cross-linking, the contents of their granules are released to the exterior and can cause a massive inflammatory reaction. The MC-restricted proteases include tryptases, chymases and carboxypeptidase A3, and these are expressed and stored at remarkably high levels. There is now emerging evidence supporting a prominent role of these enzymes in the pathology of asthma. Interestingly, however, the role of the MC-restricted proteases is multifaceted, encompassing both protective and detrimental activities. Here, the current knowledge of how the MC-restricted proteases impact on asthma is reviewed.